For internal combustion engines, timing belts are trained around gears (also known as sprockets, toothed pulleys and rotary elements) that are mounted to ends of cam shafts. Such belts require periodic replacement. To ensure that the timing relationship between the cam shafts and crank shaft of the engine is not lost, the cam shafts may need to be held against rotation whilst the belt is removed and a new timing belt is fitted.
Tools for effecting such immobilization of cam shafts are available. Often such tools are specifically designed for a particular type of engine and are not usable for other engines. This requires a selection of tools to be stocked in order to enable workshops to perform replacement of timing belts for a variety of different engines types.
U.S. Pat. No. 7,047,610 discloses a clamping device for holding a rotary element (hereafter “gear”) stationary relative to a fixed body. The clamping device has a first knob for moving a pair of clamping elements towards one another and into clamping engagement with opposing radial faces of the gear. The clamping device also has a second knob for rotating a jacking screw into engagement with the fixed body such that the gear is urged away from the fixed body.
Although the clamping device of U.S. Pat. No. 7,047,610 may be used for different types of gears, it has disadvantages in that it is of a particularly complex construction and is tedious to operate. The latter becomes more of a problem when the device needs to be used with an engine where there is little clearance between the gear and other parts of the engine.